A new study shows that employees with non-traditional work schedules are more likely to be overweight and burdened with sleep problems.
Researchers from the University of Wisconsin School of Medicine and Public Health also found that shift workers are more likely to develop metabolic disorders, such as diabetes, compared to workers following traditional work schedules.
“Shift-work employees are particularly vulnerable to experiencing sleep problems as their jobs require them to work night, flex, extended, or rotating shifts,” said lead investigator Marjory Givens, Ph.D., an associate scientist with the university.
“Shift-workers are more commonly men, minorities, and individuals with lower educational attainment and typically work in hospital settings, production, or shipping industries.”
For their study, the researchers used data from the Survey of the Health of Wisconsin (SHOW) collected from 2008-2012. SHOW is a population-based health examination survey that includes home- and clinic-based interviews and physical examinations.
In the analysis, 1,593 participants were assessed using measures from the physical examination to calculate body mass index and determine obesity or overweight status. Type II diabetes was assessed in 1,400 subjects using either the self-reporting of a physician diagnosis or glycated hemoglobin (HbA1c) 6.5 percent or higher as determined from a blood sample obtained at the physical examination.
The analysis found that shift-workers were significantly more likely than traditional schedule workers to be overweight (47.9 percent vs. 34.7 percent).
They also experienced more sleep problems, such as insomnia (23.6 percent vs. 16.3 percent), insufficient sleep (53 percent vs. 42.9 percent), or excessive wake-time sleepiness (31.8 percent vs. 24.4 percent).
Since shift-work and sleep problems have been implicated in poor metabolic health, the study also asked whether sleep problems may play a role in health disparities. The researchers found that experiencing sleep problems was positively associated with being overweight/obese or diabetic.
Moreover, even though sleep problems did not fully explain the relation between shift-work and overweight or diabetes, this association appear to be stronger among shift-workers who were not able to obtain sufficient sleep, less than seven hours a day.
This suggests that the adverse metabolic consequences of shift-work could be partially alleviated by sufficient sleep, according to the researchers.
The scientists note the study has two particular strengths: It draws from a general population sample and primary outcomes, such as being overweight or having diabetes, were defined according to objective markers, including weight, height, and HbA1c.
Potential limitations include unmeasured confounding factors, the potential for systematic biases in self-reports of sleep duration and sleep quality, and an inability to determine a causal relationship due to the cross-sectional nature of the study, the researchers added.
“This study adds to a growing body of literature calling attention to the metabolic health burden commonly experienced by shift-workers and suggests that obtaining sufficient sleep could lessen this burden,” Givens said.
“More research in this area could inform workplace wellness or health care provider interventions on the role of sleep in addressing shift-worker health disparities.”
The study was published in Sleep Health, the journal of the National Sleep Foundation.
Source: Elsevier Health Sciences